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Abstract:

A vehicle hood lining presenting at least one depression that is
preferably elongate along an edge of the lining, the depression
presenting, at a distance from its ends, at least one singularity that is
not reproduced both identically and continuously all along the length of
the depression.

Claims:

1. A vehicle hood lining, comprising: at least one elongate depression,
preferably along an edge of the vehicle hood lining, said at least one
elongate depression presenting, at a distance from its ends, at least one
singularity that is not reproduced both identically and continuously all
along a length of the said at least one elongate depression.

2. The vehicle hood lining according to claim 1, wherein said at least
one singularity is a shape singularity, said at least one elongate
depression preferably being shaped in such a manner that, if an envelope
surface is defined along said at least one elongate depression and having
a reference cross-section that is constant, then a portion of said at
least one elongate depression that is superposed on said envelope surface
presents at least one interruption or orifice.

3. The vehicle hood lining according to claim 1, wherein at least one
wall of said at least one elongate depression presents at least one
orifice, and in particular when said at least one elongate depression
presents two walls, said at least one orifice interrupts a line situated
at an intersection between two walls.

4. The vehicle hood lining according to claim 1, wherein at least one
wall of said at least one elongate depression includes at least one
projecting or recessed portion in relief, said at least one projecting or
recessed portion in relief including in particular at least one edge or
reentrant corner, and preferably being in a shape of a crenellation.

5. The vehicle hood lining according to claim 4, wherein said at least
one elongate depression includes at least two walls, and a line at the an
intersection between said at least two walls, said at least one
projecting or recessed portion in relief being contiguous with said line.

6. The vehicle hood lining according to claim 1, wherein said at least
one singularity is a material singularity, said at least one elongate
depression comprising at least a first portion made of a first material
and defining at least one orifice, and a second portion made of a second
material different from said first material and arranged in said at least
one orifice, preferably by having said first material overmolded thereon.

7. The vehicle hood lining according to claim 6, wherein said first
material is a plastics material, in particular a material selected from a
thermosetting material such as sheet molding compound and a thermoplastic
material based on polypropylene or on polyamide, optionally reinforced
with glass fibers, and/or said second material is selected from a
metallic material, such as aluminum or steel, a plastics material
distinct from said first material, and a metal-plastics composite
material, optionally including carbon or magnesium.

8. The vehicle hood lining according to claim 1, wherein said at least
one elongate depression extends essentially in a transverse direction of
said vehicle hood lining, preferably along its rear edge.

9. A vehicle hood, comprising: a lining in accordance with claim 1; and a
skin made of a metal material such as aluminum or steel or a
metal/plastics hybrid material.

10. A method of fabricating a vehicle of a hood lining, wherein at least
a portion of said hood lining is fabricated in such a manner as to
present at least one elongate depression, preferably along an edge of
said hood lining, and that said at least one elongate depression
presents, at a distance from its ends, at least one singularity that is
not reproduced both identically and in continuous manner along en entire
length of said at least one elongate depression.

11. A vehicle hood comprising: a hood skin; and a lining adapted to
receive and support said hood skin; said lining comprising a first wall,
a second wall and an intermediate surface coupling said first wall and
said second wall to define at least one elongate depression; at least one
of said first wall or said second wall being discontinuous or interrupted
to facilitate deformation of said lining.

12. The vehicle hood according to claim 11, wherein said at least one of
said first wall or said second wall comprise at least one orifice.

13. The vehicle hood according to claim 11, wherein said at least one of
said first wall or said second wall of said at least one elongate
depression includes at least one projecting or recessed portion in
relief, said at least one projecting or recessed portion in relief
including in particular at least one edge or reentrant corner and
preferably being in a shape of a crenellation.

14. The vehicle hood according to claim 13, wherein said at least one
elongate depression includes at least two walls and a line at an
intersection between said at least two walls, said at least one
projecting or recessed portion in relief being contiguous with said line.

15. The vehicle hood according to claim 11, wherein at least one
singularity is not reproduced identically and in a continuous manner
along an entire length and is a material singularity, said at least one
elongate depression comprising at least a first portion made of a first
material and defining at least one orifice, and a second portion made of
a second material different from said first material and arranged in said
at least one orifice, preferably by having said first material overmolded
thereon.

16. The vehicle hood according to claim 15, wherein said first material
is a plastics material, in particular a material selected from a
thermosetting material such as sheet molding compound and a thermoplastic
material based on polypropylene or on polyamide, optionally reinforced
with glass fibers, and/or said second material is selected from a
metallic material, such as aluminum or steel, a plastics material
distinct from said first material, and a metal-plastics composite
material, optionally including carbon or magnesium.

17. The vehicle hood according to claim 11, wherein said at least one
elongate depression extends essentially in a transverse direction along a
rear edge of said vehicle hood.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is the U.S. National Phase application of
PCT/FR2009/052055 filed Oct. 26, 2009, which claims priority to French
Application No. 0857290 filed Oct. 27, 2008, which applications are
incorporated herein by reference and made a part hereof.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a vehicle hood.

[0004] 2. Description of the Related Art

[0005] A vehicle hood is already known that comprises a skin and a lining
that are superposed. The skin is essentially plane and the lining
includes a depression extending essentially in the transverse direction
of the vehicle when the hood is mounted on the vehicle, the depression
being located at the rear end of the hood and being shaped to co-operate
with the skin of the hood to form at least one hollow body.

[0006] The lining is made of a thermosetting material such as sheet
molding compound (SMC), while the skin is made of metal, such as
aluminum.

[0007] The skin and the lining of the hood are connected together at their
respective ends by adhesive and by crimping, and they are subsequently
mounted on the vehicle.

[0008] Nevertheless, because of the intrinsic properties of the two types
of material making them up, the skin and the lining behave very
differently with respect to temperature. Thus, the hood tends to deform
when the temperature increases as a result of differential expansion
between the skin and the lining that together make up the hood. This is
particularly troublesome when the bodywork passes through cataphoresis,
during which the bodywork and the hood mounted thereon are immersed in a
bath and then pass through a stove at very high temperature. While in the
stove, the skin expands more than the lining, which is attached to the
skin at each of its ends, thereby giving rise to deformation of the hood.
In addition, if provision is made for adhesive to be cured while the hood
is passing through the stove, the skin and the hood are held stationary
relative to each other in a deformed configuration of the hood, and that
is unsatisfactory since it is no longer possible to return the hood to
its normal shape on cooling.

[0009] The problem of remanent deformation associated with differential
expansion is analogous when the skin and the lining are made of other
materials. In particular, the problem also exists for a skin made of
steel and a lining made of thermoplastic material, except that under such
circumstances, it is the lining that expands more than the skin.

[0010] What is needed, therefore, is a system, method and lining that
overcomes one or more of the problems mentioned.

SUMMARY OF THE INVENTION

[0011] An object of the invention is to remedy those drawbacks by
providing a lining that makes it possible to limit, or even avoid,
deformation of the hood after passing to a high temperature and cooling.

[0012] To this end, one embodiment of the invention provides a vehicle
hood lining presenting at least one elongate depression, preferably along
an edge of the lining, the depression presenting, at a distance from its
ends, at least one singularity that is not reproduced both identically
and continuously all along the length of the depression.

[0013] Naturally, the at least one singularity is present in the initial
state of the lining, and a hood lining that has been subjected to an
impact and that presents a singularity solely as a result of that impact
does not constitute a lining of the invention.

[0014] Such a singularity modifies the section of the depression locally.
An orifice or a portion in relief may form such a singularity. In
contrast, an edge or a reentrant corner in the depression, located at the
intersection between two walls of the depression, is a singularity, but
one that is reproduced identically and continuously over the entire
length of the depression.

[0015] Since the depression is the most rigid portion of the lining, it is
the depression that guides deformation of the lining.

[0016] Thus, by providing at least one singularity in the depression,
e.g., an orifice, the wall(s) of the depression are not solid and
continuous, as happens in the prior art, thereby facilitating deformation
of the lining.

[0017] The hood lining thus follows expansion of the skin more easily and
the deformation induced in the hood by differential expansion is thus
diminished.

[0018] As a result, when the skin and the lining are connected together by
adhesive, and if the adhesive is cured while the hood is passing through
the cataphoresis stove, the relative positioning of the skin and the
lining while they are being held stationary relative to each other
remains satisfactory, since the deformation of the hood is less.

[0019] The invention also makes it possible to achieve this result when it
is the lining that deforms more than the skin.

[0020] In addition, since the deformation of the hood is less, if the skin
and the lining are already held stationary relative to each other because
the adhesive that bonds them together is already cured, then when they
pass through the cataphoresis stove the stresses to which the lining is
subjected are smaller and the behavior of the hood over time is improved.

[0021] When the skin and the lining are connected together by adhesive,
the invention also makes it possible to reduce the shear stresses that
appear in the adhesive or at the interface between the adhesive and the
skin or the lining as a result of the hood deforming as it passes through
cataphoresis, thereby improving the fastening of the skin relative to the
lining.

[0022] The invention also presents one or more of the characteristics in
the following list:

[0023] The lining is dimensioned to be superposed over the skin over
substantially the entire area of the skin. In particular, the lining has
a plurality of elongate depressions extending in distinct longitudinal
directions.

[0024] The depression includes at least two and preferably at least three
singularities, thereby optimizing the influence of these singularities on
the behavior of the hood in the event of it expanding.

[0025] The singularity is a shape singularity, the depression preferably
being shaped in such a manner that, if an envelope surface is defined
along the depression and having a reference cross-section that is
constant, then the portion of the depression that is superposed on the
envelope presents at least one interruption or orifice.

[0026] At least one wall of the depression presents at least one orifice.
Because of the empty space that it forms in the wall, such an orifice
facilitates deformation of the lining and reduces the stresses to which
it is subjected. The orifice is particularly advantageous for absorbing
compression expansion of the lining. When the lining passes through
cataphoresis, its strength is degraded because of the high temperature
and the lining tends to sag under the effect of its own weight. This
effect opposes the thermal expansion of the hood and certain portions of
the lining are subjected to compression as a result of this phenomenon.
The presence of orifices thus makes it possible to allow greater
deformation of the lining, more particularly in compression, and to
reduce the stresses generated therein as a result of it sagging. These
orifices also serve to position and hold cables relative to the lining.

[0027] In particular, the depression comprises at least two walls and a
line of intersection between these two walls, with the orifice
interrupting the line. This is particularly advantageous since the
stresses due to the deformation of the hood are particularly concentrated
at the edges and the reentrant corners of the depression. Such an orifice
"breaks" the shapes of those elements and allows the lining to deform
more easily and enables the stresses to which it is subjected to be
reduced.

[0028] At least one wall of the depression includes at least one
projecting or recessed portion in relief. In particular, the portion in
relief includes at least one edge or reentrant corner and is preferably
in the shape of a crenellation. The presence of an edge or of a reentrant
corner that projects or is recessed relative to the main wall of the
depression enables the lining to fold and unfold at the edge or the
reentrant corner. This therefore facilitates deformation of the
depression and consequently of the lining, thereby reducing the stresses
generated therein as a result of the differential expansion. Furthermore,
with such portions in relief, the stiffening properties of the hollow
body formed using the depression are better than when the singularity is
in the form of an orifice.

[0029] The depression includes at least two walls with a line of
intersection between those two walls, the portion in relief being
contiguous with the line. Such a conformation for the lining enables
stresses to be reduced at the edges or reentrant corners of the
depression, a zone in which stresses are particularly concentrated.

[0030] The depression presents a first thickness in a zone contiguous with
the portion in relief, while the portion in relief presents a second
thickness that is smaller than the first thickness. By reducing the
thickness of the portion in relief, deformation of the lining is made
still easier.

[0031] The singularity is a material singularity. In particular, the
depression presents a first portion made of a first material and defining
at least one orifice, and a second portion made of a second material
different from the first material and arranged in at least one of the
orifices, preferably by being embedded in the first material by
overmolding. The second portion is preferably made out of the same
material as the skin of the hood. A lining presenting a material
singularity, in particular when one of the two materials is a metal or a
glass fiber reinforced plastics material, presents very good rigidity,
thereby increasing the strength of the lining so as to reduce its sagging
under the effect of its own weight while passing through cataphoresis. In
addition, when the shape and the material of the second portion are
suitably selected, they serve to assist the depression in expanding as
much as the hood. For example, for a hood made of an aluminum hood and a
lining presenting a first portion made of plastics material, e.g., of
SMC, and a second portion made of aluminum, the second portion of the
depression tends to expand more than the first portion and to allow the
lining to expand in a manner that is closer to the manner in which the
skin expands so as to avoid deforming the hood. It is also possible for
the second portion to present a stamped shape or to be superposed on the
first portion of the depression.

[0032] Projecting from a wall of the depression, the lining includes a rib
that preferably extends essentially vertically downwards when the lining
is mounted on the vehicle, the rib carrying in particular a sealing
gasket at a free end. The rib thus also serves to prevent, or at least to
limit, any sagging of the lining as a result of its own weight, since it
bears against parts that form part of the vehicle bodywork, thereby
enabling the hood to be held in position. The sealing gasket also serves
to provide sealing in the scuttle zone of the hood, when the depression
is situated in the rear portion of the hood and extends in the transverse
direction thereof, thereby establishing hermetic separation between the
vehicle cabin and the vehicle engine compartment.

[0033] The first material is a plastics material, in particular a
thermosetting material such as sheet molding compound (SMC), whereas the
second material is a metal material, such as aluminum or steel.

[0034] The first material is a plastics material, selected in particular
from a thermoplastic material based on polypropylene or on polyamide and
optionally reinforced with glass fibers, while the second material is
selected from a metal material such as aluminum or steel, a plastics
material distinct from the first material, and a metal-plastics composite
material and/or including carbon or magnesium.

[0035] The depression extends essentially along the transverse direction
of the hood, preferably along its rear edge.

[0036] The invention also provides a vehicle hood comprising:

[0037] a lining in accordance with the invention; and

[0038] a skin made from a metal material such as steel, aluminum, or a
metal/plastics hybrid material.

[0039] In addition, the lining and the skin of the hood of the invention
may be connected together at each of the ends of the depression.

[0040] Optionally, the second material of the lining is the same as the
material constituting the skin.

[0041] The invention also provides a method of fabricating a vehicle
lining, wherein the lining is fabricated in such a manner as to present
at least one elongate depression, preferably along an edge of the lining,
and that the depression presents, at a distance from its ends, at least
one singularity that is not reproduced both identically and in continuous
manner along the entire length of the depression. Such a method enables
the lining of the invention to be fabricated.

[0042] Optionally, with a lining that is designed to be molded using a
first material, an element made of a second material is placed in a mold
for fabricating the lining, in particular an element made of a metal
material, such that the element forms a portion of the depression, once
the lining has been molded. By overmolding an element made of a different
material in this way, the different material preferably being the same as
the material of the skin, it is possible to influence the expansion of
the lining and to reduce the differential expansion of the hood and its
deformation at high temperatures.

[0043] Advantageously, the second material is different from the material
of the skin, but is selected in such a manner that the overall behavior
of the lining in expansion is very similar to that of the skin.

[0044] These and other objects and advantages of the invention will be
apparent from the following description, the accompanying drawings and
the appended claims.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0045] The invention can be better understood on reading the following
description given purely by way of example and made with reference to the
drawings, in which:

[0046]FIG. 1A is a schematic plan view of a lining in an embodiment of
the invention;

[0047]FIG. 1B is a perspective view of a portion of the FIG. 1A lining;

[0048] FIG. 2 is a section view on plane II-II of the FIG. 1B lining, when
assembled with the skin;

[0049]FIG. 3 is a perspective view of a detail of a lining in a second
embodiment of the invention;

[0050]FIG. 4 is a perspective view of a detail of a lining in a third
embodiment of the invention;

[0051]FIG. 5 is a perspective view of a detail of a lining in a fourth
embodiment of the invention; and

[0052]FIG. 6 is a view of a hood including a lining in a fifth embodiment
of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0053]FIG. 1A is a diagrammatic view of a hood lining 10 that is to
extend essentially over the entire area of the hood and thus line the
skin over essentially all of its area. The hood lining 10 includes a
peripheral depression 12 that includes in particular an elongate rear
portion 14 extending essentially in the transverse direction of the hood
in the vicinity of the rear of the hood, in particular along its rear
edge. This depression 12, in particular the portion 14, contributes a
large fraction of the stiffnesses of the hood.

[0054] As can also be seen in FIG. 1A, the hood lining 10 includes
locations 18, 20A, and 20B that constitute points for attaching the hood
to the bodywork. The location 18 is situated in the front portion of the
depression 12, in the center of the front edge of the hood lining 10, and
serves to receive a lock, and the locations 20A and 20B, each situated in
one of the rear corners of the hood lining 10, in the portion 14, serve
to receive the hinges.

[0055] As can be seen more particularly in FIG. 1B, showing a detail of a
rear corner of the hood lining 10, the portion 14 of the depression 12
presents a U-shaped cross-section with its concave side being designed to
face towards the hood skin 30 of the hood when the hood skin 30 and the
hood lining 10 are assembled together.

[0056] The portion 14 comprises in particular a bottom wall 22 that is
essentially parallel to a central portion 23 of the lining 10 and two
side walls 24 that connect the bottom 22 to the remainder of the hood
lining 10.

[0057] As can be seen in FIG. 2, when the hood lining 10 and a hood skin
30 are assembled together, the portion 14 co-operates with the hood skin
30 to form a hollow body 26, together defining a cavity. In addition, the
hood skin 30 and the hood lining 10 are assembled to each other on either
side of the depression 12 using a plastics filler 32 along a longitudinal
edge 10a of the hood lining 10 beside the depression 12 adjacent to the
central zone of the hood lining 10, or an adhesive 34 that is curable
using moisture, possibly when hot, along the other longitudinal edge of
the hood lining 10, adjacent to the edge of the hood. In addition, at the
end of the hood lining 10 beside the depression 12, the hood skin 30 and
the hood lining 10 are crimped together, i.e., the hood skin 30 is folded
over so as to be clamped around the hood lining 10. At the ends of the
depression 12 along its longitudinal direction, the hood skin 30 and the
hood lining 10 are also secured to each other, in particular using an
adhesive and crimping. The hood skin 30 is made of a metal material, such
as steel or aluminum.

[0058] The depression 12 also includes two orifices 36A, 36B (FIG. 1B)
that form shape singularities. These orifices 36A, 36B are formed both
through the bottom wall 22 and through one of the side walls 24 of the
depression 12, in this example the wall closer to the central zone of the
hood lining 10. Thus, each of the orifices 36A, 36B interrupts a line 37
forming a reentrant corner marking the join between the bottom wall 22
and the side wall 24.

[0059] As can be seen in FIG. 2, the hood lining 10 also has reinforcement
38 at the ends of the portion 14 along its longitudinal direction and in
the rear corners of the hood lining 10, the reinforcement 38 comprising
fastener orifices 40 (visible in FIG. 1B) enabling the hinges to be
fitted to the hood lining 10 by means of fastener screws.

[0060] As can be seen in FIG. 2, this reinforcement 38 is stamped to
present a U-shaped section so as to be superposed on the portion 14 at
its end in its longitudinal direction.

[0061] The lining, and in particular the portion 14, is made of a plastics
material, in particular a thermosetting material such as sheet molding
compound (SMC), while the reinforcement 38 is made of a metal material
such as aluminum or steel, the material preferably being the same as the
material constituting the hood skin 30.

[0062] Thus, when the hood made up of the hood lining 10 and the hood skin
30 is subjected to cataphoresis, in particular in a stove for drying the
bodywork after a cataphoretic bath, the hood is raised to a high
temperature and the hood skin 30 and the hood lining 10 expand.
Nevertheless, since the hood skin 30 and the hood lining 10 are not made
of the same material, differential expansion occurs between those two
elements. When the hood skin 30 is made of aluminum, it expands much more
than does the hood lining 10 since the hood lining 10 is made of SMC.

[0063] As a result of the orifices 36A, 36B formed in the depression 12,
it is easier for the hood lining 10 to deform. The hood lining 10 can
then follow the deformation of the hood skin 30 more easily.

[0064] In addition, because of the presence of the reinforcement 38 inside
the portion 14, the reinforcement 38 being made of a metal material and
thus tending to expand more than the hood lining 10, in particular if it
is made of aluminum, the expansion of the depression 12 is closer to that
of the hood skin 30 such that the hood lining 10 follows the hood skin 30
more easily.

[0065]FIG. 3 shows a depression 50 of a motor vehicle hood lining 10 in a
second embodiment of the invention.

[0066] Like the depression 12 in the first embodiment, the depression 50
extends substantially in the transverse direction of the hood. It
presents a cross-section that is U-shaped and comprises in particular a
bottom wall 52 and two side walls 54.

[0067] An envelope surface having a U-shaped cross-section given reference
48 as shown in FIG. 3 is defined from the hollow body and it follows a
director line of the depression 50, where one such director line is drawn
as a dashed line in FIG. 1A.

[0068] On one of its side walls 54, the depression 50 includes two
portions in relief 56 that are hollow when seen from the inside of the
depression 50. Thus, the portion of the depression 50 that is superposed
on the envelope surface 48 has two orifices corresponding to the
locations at which the portions in relief 56 are formed on the depression
50.

[0069] Each of these two portions in relief 56 presents a cross-section in
the X-Y plane that is U-shaped and forms a shape singularity in the
depression 50. The longitudinal direction of these portions in relief 56
extends essentially perpendicularly to the longitudinal direction of the
depression 50, and corresponds in particular to a vertical direction when
the hood lining 10 is assembled in the closed position on the vehicle.
Each portion in relief 56 comprises in particular a plane end wall 56B
and two likewise plane side walls 56A, and it presents edges 58 that
extend essentially in the vertical direction.

[0070] Thus, the side wall 54 of the depression 50 is in the form of a
crenellation. Such a shape facilitates deformation of the depression 50
since the portions in relief 56 can fold and/or unfold at their edges 58.
In addition, the stiffness of the hood is not significantly reduced.

[0071] A lining in a third embodiment of the invention is described below
with reference to FIG. 4.

[0072] The depression 60 in the hood lining 10 is of a shape similar to
that of the first and second embodiments, i.e., it is essentially
elongate in shape and presents a U-shaped cross-section. It also includes
a bottom wall 62 and two side walls 64. As above, a U-shaped reference
section 66 is defined from the depression 60 and extends along the
director line of the depression 60.

[0073] This depression 60 also has a hollow portion in relief 68 forming a
shape singularity in the depression 60. This portion in relief 68 is
formed over the entire cross-section from one side wall to the other,
i.e., over the entire transverse dimension of the bottom wall 62 and also
of the side walls 64 of the depression 60.

[0074] This portion in relief 68 is in the form of a groove or trough
extending perpendicularly to the longitudinal direction of the depression
60 and presenting a cross-section in the Y-Z plane in the bottom wall 62
and in the X-Y plane in the side walls 64, forming portions of a circle.
It is shaped in such a manner that the portion of the depression 60 that
is superposed on the envelope surface is interrupted in its portion
including the portion in relief 68.

[0075] This portion in relief 68 is contiguous with the reentrant corners
or lines 70 of the depression 60 marking the joins between the bottom
wall 62 and the side walls 64 and it intersects them, such that these
lines 70 are not rectilinear.

[0076]FIG. 5 shows a depression 71 of a hood lining 10 in a fourth
embodiment of the invention. Such a depression 71 is of generally
elongate shape and it presents a U-shaped cross-section. It has a bottom
wall 72 and two side walls 74. It also has a portion in relief 76
projecting from the bottom wall 72 and forming a singularity in the form
of a hollow body. This portion in relief 76, as in the second embodiment,
forms a crenellation. It extends into the depression 71 such that a wall
77 of the portion in relief 76, extending essentially parallel to the
bottom 72 of the depression 71, thus comes closer to the hood skin 30
when the hood lining 10 and the hood skin 30 are assembled together than
does the bottom wall 72 of the depression 71.

[0077] The hood lining 10 also includes a rib 78 projecting from the
bottom wall 72 of the depression 71, the rib 78 being essentially
perpendicular to the bottom wall 72, parallel to its longitudinal
direction, and extending vertically downwards when the hood is assembled
on the vehicle. At its free end, this rib 78 includes a sealing gasket 79
for resting on at least one element of the engine compartment when the
hood is arranged on the vehicle. This sealing gasket 79 serves to isolate
the hood from the vehicle cabin when the depression 71 is located on the
hood in the same manner as the portion 14 on the hood of FIG. 1. In
addition, since the rib 78 bears against parts inside the engine
compartment, it serves to limit the extent to which the hollow body sags
under the effect of its own weight, which phenomenon occurs when the hood
is raised to a high temperature, e.g., during cataphoresis.

[0078] Another embodiment of the invention is described below with
reference to FIG. 6.

[0079] In this embodiment, the hood lining 10 includes a depression 90 of
shape similar to that of the other depression, i.e., it extends
substantially in a main direction and presents a U-shaped cross-section.
It has a bottom wall 92 and two side walls 94.

[0080] This depression 90 includes a first portion 96 made of plastics
material, e.g., of SMC, and presents an orifice 97 formed in the bottom
wall 92 thereof.

[0081] As can be seen in FIG. 6, the hood lining 10 presents a material
singularity. The orifice 97 formed in the plastics material is filled
with a second portion 98 that is made of a metal material and that is
arranged in the hood lining 10 to fill the orifice 97 formed in the
plastics material portion of the depression 90. In particular, as can be
seen in FIG. 6, this second portion 98 is constituted by a metal plate,
the metal plate being embedded in the hood lining 10 during molding such
that its position relative to the remainder of the hood lining 10 is
accurately determined. A plurality of singularities of this type may be
provided in the depression 90. In this manner, each metal plate placed in
an orifice of a plastics portion of the depression 90 may be made of a
material that enables it to expand to a greater or lesser extent than the
plastics portion of the depression 90 and at a selected ratio, such that
the hood lining 10 follows the expansion of the hood skin 30 during the
stoving operation of cataphoresis, during which the hood is raised to a
high temperature. The metal plate formed in each of the orifices are thus
preferably made of the same material as the hood skin 30 or of a material
that expands to a greater extent.

[0082] The invention is not limited to the embodiment described above.

[0083] The hood skin 30 and the hood lining 10 may be made of materials
other than those described. For example, the hood lining 10 may be made
of a thermoplastic material placed on polyamide or on polypropylene,
possibly reinforced by glass fibers. The hood skin 30 may be of a metal
material other than those described, or indeed it may be made of a
plastics material. The hood lining 10 and/or the hood skin 30 may also be
made using a hybrid material comprising both a plastics material and a
metal material, and possibly carbon or magnesium.

[0084] The hood skin 30 may also be made of a thermoplastic material and
the hood lining 10 may be made of a metal material, the hood skin 30 then
expanding less than the hood lining 10. Under such circumstances, the
hood lining 10 may include a material singularity, the second portion of
the material being made of a material that expands less than the hood
skin 30.

[0085] In addition, the shapes of the depressions are not limited to those
described, nor indeed are they limited in their locations relative to the
hood. For example, the depressions may be of V-shaped section, and/or
they may extend essentially in the longitudinal direction of the hood.

[0086] Furthermore, the shapes of the portions in relief, their locations,
or their distributions are not limited to those described. By way of
example, they may be of V-shaped section or they may be of concertina
shape. The shape of the orifices are not limited to the shapes described.
They may be formed in one wall only, for example.

[0087] Similarly, when the singularity is a material singularity, the
metal portion may be formed both on a portion of the bottom 92 of the
depression and a portion of at least one of the side walls 94 of the
depression, e.g., being of a shape that is complementary to the orifice
36A, 36B shown in FIG. 1B. The metal portion is then obtained by stamping
or folding and is formed in the mold for making the plastics lining.

[0088] In addition, the numbers of portions in relief or orifices is not
limited to those described above. In particular, it is advantageous for
the depression to present at least three singularities in order to
facilitate deformation of the hood lining 10. These elements may also be
present in combination in the hood lining 10.

[0089] When the depression presents at least one portion in relief, it may
also present a first thickness in the portion that is superposed on the
envelope surface, contiguous with the portion in relief, and a smaller
second thickness in the portion forming the relief, in particular at its
edges, thereby further facilitating deformation of the lining.

[0090] It should also be observed that the metal reinforcement(s) present
in the lining may be of any shape other than those described or may be
located in positions other than those described. By way of example, a
single piece of metal reinforcement may extend over the entire length of
the depression 14, etc.

[0091] While the system, apparatus and method herein described constitute
preferred embodiments of this invention, it is to be understood that the
invention is not limited to this precise system, apparatus and method,
and that changes may be made therein without departing from the scope of
the invention which is defined in the appended claims.